Implementation of New or Revised Ozone and Particulate Matter (PM) National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations

SUMMARY: The EPA is providing advance notice of key issues for

consideration in the development of new or revised policies and/or

regulations to implement revised NAAQS for ozone and PM, and

development of a regional haze program. The EPA is under court order to

issue a proposed decision on whether to retain or revise the PM NAAQS

by November 29, 1996, and to issue a final rulemaking for PM by June

29, 1997. The Agency anticipates following the same schedule for the

ozone standard and also intends to propose a regional haze program in

mid-1997. If revised NAAQS replace existing NAAQS, there would be a

period of time to phase in new requirements while continuing to address

the requirements of the current programs. Further, ozone, PM and

regional haze are products of interrelated chemical conversions in the

atmosphere, and new approaches will be needed to identify and

characterize affected areas and to assign planning, management and

control responsibilities. This could lead to integrated implementation

policies for ozone, PM and regional haze control programs. This ANPR

provides a broad scientific and policy perspective on these issues and

addresses implementation issues that have been identified, such as the

need for regional strategies, and is a continuation of the advisory

process first announced on September 11, 1995 (60 FR 47171) and further

explained by the Agency on June 12, 1996 (61 FR 29719). Through today's

action, the Agency is providing a brief discussion of a broad range of

options, principles and questions related to each of these key issues.

The options/principles/questions in this ANPR were designed to provide

sufficient background information to stimulate public interest and

comments and are not intended to indicate preferences or decisions by

the EPA. By publishing this information at this time, the EPA is

providing more time for the public to develop input and comments than

would occur following the publication of the subsequent regulatory

notices for the implementation strategies and regional haze program. An

explanation and structure of the Federal Advisory Committee Act (FACA)

Subcommittee is provided in SUPPLEMENTARY INFORMATION. Applicable terms

and definitions are provided in the Appendix.

DATES: Written comments on this proposal must be received by February

18, 1997.

ADDRESSES: Comments. Comments should be submitted (in duplicate if

possible) to the Air and Radiation Docket and Information Center, 401 M

Street, SW, Washington, DC 20460, Attention Docket Number A-95-38.

Docket. The public docket for this action is available for public

inspection and copying between 8:00 a.m. and 4:00 p.m., Monday through

Friday, at the Air and Radiation Docket and Information Center (6102),

Attention Docket A-95-38, South Conference Center, Room 4, 401 M

Street, SW, Washington, DC 20460. A reasonable fee for copying may be

charged.

FOR FURTHER INFORMATION CONTACT: For general FACA Subcommittee

questions and comments, contact Ms. Denise Gerth, U.S. EPA, MD-15,

Research Triangle Park, NC 27711, telephone (919) 541-5550. For

specific questions and comments on the ANPR, contact Ms. Sharon

Reinders, U.S. EPA, MD-15, Research Triangle Park, NC 27711, telephone

(919) 541-5284.

SUPPLEMENTARY INFORMATION: The following communications and outreach

mechanisms have been established:

Overview information--A World Wide Web (WWW) site has been

developed for overview information on the NAAQS and the ozone/PM/

regional haze FACA process. The Uniform Resource Location (URL) for the

home page of the web site is http://www.epa.gov/oar/faca/

Detailed and technical information--Available on the O3/PM/RH

Bulletin Board on the Office of Air Quality Planning and Standards

(OAQPS) Technology Transfer Network (TTN), which is a collection of

electronic bulletin board systems operated by OAQPS containing

information about a wide variety of air pollution topics. The O3/PM/RH

Bulletin Board contains separate areas for each of the FACA

Subcommittee's five work groups and includes meeting materials, issue

papers, as well as general areas with information about the process,

participants, etc. The TTN can be accessed by any of the following

three methods:

--By modem; the dial-in number is (919) 541-5742. Communications

software should be set with the following parameters: 8 Data Bits, No

Parity, 1 Stop Bit (8-N-1) 14,400 bps (or less).

--Full Duplex.

--ANSI or VT-100 Terminal Emulation.

The TTN is available on the WWW site at the following URL: http://

ttnwww.rtpnc.epa.gov. The TTN can also be accessed on the Internet

using File Transfer Protocol (FTP); the FTP address is

ttnftp.rtpnc.epa.gov. The TTN Helpline is (919) 541-5384.

I. Purpose and Objectives

This ANPR outlines policy and technical implementation issues and

identifies a broad range of options/principles/questions for each issue

associated with the potential revision of the ozone and PM NAAQS and

with the development of a regional haze program. Although the proposals

to change the ozone and PM NAAQS have been made, the possibility that

such changes may be promulgated necessitates this advance notice, as

well as the ongoing implementation discussions under the FACA discussed

elsewhere in this notice. The alternative approach of waiting until

possible standard revisions are actually promulgated would, in the

Agency's judgement, cause inevitable delays and disruptions in

national, State and local efforts to achieve clean, healthy air,

especially those related to attainment of the NAAQS for ozone. The

ozone and PM NAAQS proposals are scheduled for publication in December

1996 with final action scheduled for mid-1997. The EPA intends to

propose a regional haze program in mid-1997.

In advance of these actions, the EPA published an ANPR entitled,

National Ambient Air Quality Standards for Ozone and Particulate

Matter, on June 12, 1996 (61 FR 29719) which announced the Agency's

plans to propose decisions on whether to retain or revise the ozone and

PM NAAQS. That ANPR also described the FACA process and the

Subcommittee for Ozone, PM and Regional Haze Implementation Programs

(Subcommittee). The Subcommittee is composed of 60 representatives from

State, local and tribal organizations; environmental groups, industry

and trade groups (including small business representatives),

consultants; academic/scientific communities; and Federal agencies. The

organization of the Subcommittee includes a Coordination

[[Page 65765]]

Group and four work groups: (1) Base Programs Analyses and Policies

Work Group, (2) National and Regional Strategies Work Group, (3)

Science and Technical Support Work Group, and (4) Communications and

Outreach Work Group. The Subcommittee was established under the Clean

Air Act Advisory Committee (CAAAC) to provide advice and

recommendations to the EPA on developing new, integrated approaches for

implementing potential revised NAAQS for ozone and PM, as well as for

implementing a new regional haze reduction program. Through this

process, EPA is engaging in communications with segments of society

that may be affected by the implementation of NAAQS and the regional

haze program. This announcement is a further attempt to invite

stakeholders to participate in the implementation development process,

to assure that their concerns will be addressed and their options

assessed, and, ultimately increase the effectiveness of NAAQS

implementation strategies and the regional haze program.

The implementation issues described in this ANPR form the basis of

the Subcommittee's deliberations and for the most part were developed

through the various work groups and the Coordination Group. The

presentation of these issues and corresponding options/principles/

questions is designed primarily to provide advance notice for the

public who are not directly involved in the FACA process. Interested

readers are directed to EPA's TTN and WWW site for an up-to-date status

of the work groups' and Subcommittee's deliberations on these issues.

This includes work group issue papers with options and, where

appropriate, draft recommendations.

While the EPA is interested in considering new and innovative

approaches to implementation, it is imperative to ensure that momentum

is maintained in the current implementation programs, and that current

programs and efforts such as the Ozone Transport Assessment Group

(OTAG) continue in order to protect public health and welfare. As a

consequence, the Subcommittee is providing recommendations to EPA

regarding the development of an interim implementation policy (IIP),

which was published in December 1996. The IIP will provide EPA's

guidance to the State and local agencies on appropriate actions during

the transitional period of time between any revision of the NAAQS and

the development of new integrated implementation strategies. This is

especially important since it is expected that any new NAAQS will be at

least as stringent as the current NAAQS, and reductions in emissions to

achieve the current NAAQS will be beneficial in achieving the revised

NAAQS. While the IIP will provide guidance during the transition

period, EPA will also develop implementation strategies for the

potential new ozone/PM/regional haze programs.

The final integrated implementation programs for ozone, PM and

regional haze are being developed in two phases. In Phase I, the air

quality management framework issues will be addressed (proposal--mid-

1997). Phase II will focus on more detailed control strategy

development (proposal--mid-1998). These phases are described in more

detail in subparagraph IV.

II. Scientific and Technical Discussion

The following discussion relies on the Scientific and Technical

Support Work Group of the FACA Subcommittee. This group is developing a

draft conceptual model framing our current scientific understanding of

ozone, fine particles and haze, the associated gaps and uncertainties,

and based on the technical basis and issues underlying the integration

of regulatory programs for ozone, fine particles and regional haze, and

the specification of geographic scales required for air quality

management. This conceptual model provides a technical basis for the

Subcommittee's deliberations of these issues. This document is

undergoing further review prior to acceptance by the CAAAC. Regarding

the rationality of integration, the initial response of the Science and

Technical Support Work Group was a qualified yes, given the regional

nature of the pollutants (i.e., regionalization), spatial patterns of

air quality indices, precursors, sources, atmospheric chemistry and

meteorological processes which affect more than one pollutant, and

control options. The following discussion focuses on the relationships

between ozone and fine particles, given the close linkage between fine

particle levels and regional haze (the widespread impairment of

visibility in every direction, mostly attributed to fine particle light

scattering and absorption), with the following assumptions:

--Understanding the emission sources and atmospheric processes which

are responsible for elevated air pollutant levels requires an

examination of urban and regional geographical scales;

--Ozone and fine particles may exhibit similar spatial patterns,

although the frequency (and importance) of concurrent patterns is not

well understood;

--Many of the emission precursors (and sources of precursors) to ozone,

fine particles and regional haze are the same;

--Many of the atmospheric processes (chemistry and meteorology)

affecting ozone, fine particles, and regional haze are the same; and

--Several critically-important information gaps exist which create very

difficult challenges for air quality management of these pollutants.

A. Interacting Spatial Scales of Emissions, Atmospheric Processes and

Air Quality Indices

As explained in greater detail below, there are a variety of

emissions that are precursors to elevated levels of ozone, fine

particles, and regional haze and of sources to these emissions.

Historically, attempts at air quality management of these problems

focused on local sources in the context of an anonymous background term

quantifying imported air quality. The evolution in our understanding of

the spatial and temporal scales of the effects on ozone, fine

particles, and regional haze of the emissions from all sources has,

however, spawned the recognition of the need for a larger geographical

perspective. This larger geographical perspective, which considers

individual sources over regional, as well as local scales, is needed to

support quantitative analysis of the relative contribution of the

various source types and of their emission types (species) that

contribute to nonattainment levels and regional haze. The need for an

altered perspective has been recognized by the establishment of the

Ozone Transport Commission (OTC), the OTAG, and the Grand Canyon

Visibility Transport Commission (GCVTC).

Air quality management in the metropolitan statistical area or

consolidated metropolitan statistical area (MSA or CMSA) has worked

well historically to control the local source effect on nonattainment

problems. This is evidenced by the significant decrease in the number

of ozone nonattainment areas over the past decade. As these controls

have reduced emissions and as modeling tools have progressed, the role

of the effect of sources beyond the MSA or CMSA and the varying spatial

scales of air quality indices and atmospheric processes continue to be

investigated and supported by a strong body of scientific evidence:

--The 1991 National Academy of Science (NAS) Report, Rethinking Ozone

in Urban and Regional Scales

[[Page 65766]]

(National Research Council (NRC), 1991);

--The 1993 NAS Report, Protecting Visibility in National Parks and

Wilderness Areas (NRC, 1993);

--The National Acid Precipitation Assessment Program (Trijonis et al.,

1990); and

--The Southern Oxidant Study (Chameides and Cowling, 1995).

Recent analyses based on ambient air monitoring data (Rao, 1995)

and regional acid deposition model air quality modeling (Appleton,

1995) suggest a very broad spatial air pollution region covering the

greater part of the Eastern United States (U.S.). These studies

indicate that, while sources still have their largest influence in the

near field, the zones of potential influence of source regions (e.g.,

an urban city) can under certain conditions extend out hundreds of

kilometers (km) for ozone, fine particles, and regional haze. Moreover,

these scales appear to be similar for ozone and fine particles. In

other words, sources once thought to be remote with respect to

nonattainment levels of ozone, fine particles, and regional haze are

seen as potential contributors to those levels. The analyses suggest

that chemical and meteorological processes which influence pollutant

generation, air mass movement and pollutant removal (e.g., clouds and

precipitation) are key factors in defining regional zones of influence.

When the various nonattainment areas of the Eastern U.S. are surrounded

by even conservative estimates of the zones of influence of these other

sources, what results is a modeling domain that may span the greater

part of the Eastern U.S. Accordingly, efficient air quality management

requires addressing these additional sources, atmospheric processes and

related impacts as scales of interactions over multiple spatial and

temporal frames.

In air quality management practice, the term ``transport'' has been

used in a very broad context beyond the strict meteorological

definition of the term. This broad context includes: (1) The overall

regionalization of both the scale of pollutant distributions and zone

of influence of sources, (2) the interaction (or effect of one area on

another) among local, urban and regional source scales, and (3) meso

and large-scale meteorological phenomena (such as recirculation due to

stagnant high pressure systems and land-sea interactions, large-scale

movement of air masses with fairly uniform motion, and other events

perhaps as simple as widespread elevated temperatures). The prevalence

and importance of biogenic volatile organic compounds (VOC) emissions

(e.g., emissions from trees) in the Eastern U.S. are ``regionwide,'' as

are many other area source emissions such as those emitted by motor

vehicles. All of these regional attributes are enhanced by the

relatively flat and consistent terrain in the East and Midwest,

contrasting the greater topographic and meteorological effects in the

Western U.S., although the West can also experience regional problems.

Several physical and chemical events act together in determining

pollutant concentrations over multiple space and time scales. Moving

air masses carry all chemical species including precursors, fast-

reacting intermediates, and chemical sinks, as well as the specific

pollutant species of interest (e.g., fine particles and ozone). Removal

of pollutants occurs continuously through deposition. Also, the impact

of these pollutants is not simply additive. Ozone (or precursors)

transported from one location can affect ozone levels downwind by

indirectly accelerating atmospheric chemical reactions through the

production of chemical intermediates (e.g., hydroxyl radicals). Clouds

play several roles in modifying concentrations by: (1) Dissolving

soluble gases (e.g., nitric acid, sulfur dioxide (SO2), hydrogen

peroxide) and generating aerosols through aqueous phase reactions, (2)

circulating and venting pollutants to high altitudes where strong winds

promote large horizontal transport, and (3) removing pollutants through

precipitation. Cloud-related dissolution and transport also contribute

to pollutant removal. Vertical air mass movements, or phenomena as

basic as the daily mixed layer growth, affect air concentrations on

various scales. Superimposed on these processes are a variety of

emission sources with their own spatial, temporal and component

(speciation) scales. Depending on location, pollutant and season, one

particular spatial scale (e.g., urban) may (or may not) exert a

dominating influence on air quality relative to another scale (e.g.,

regional). Even in cases where local and urban sources are responsible

for most of the ``local'' air quality, an assessment of the

contribution of distant sources to local air quality is required to

reach such a conclusion. Thus, to avoid the exclusion of potentially

important considerations in air quality analysis, ``regionality'' or

``interacting scales'' is a more descriptive term (than transport)

which encompasses the broader meaning and effects of several complex

interacting phenomena operating over extensive and multiple time and

space scales.

The Eastern U.S. differs markedly, topographically and

climatologically, from the West, so any extension to the West based on

Eastern analyses (or vice versa) is not necessarily appropriate

(important differences exist between Northern and Southern regions as

well). The monitoring data and modeling analyses of the GCVTC process

highlight the challenge of identifying and quantifying specific

sources, some at great distances in order to estimate their effects in

Western national parks and wilderness areas. The variations in

topography, meteorology and source distribution across regions require

that area- and case-specific differences be accounted for in any air

management approach. The effects of emission reduction strategies

should be viewed through multiple scales, considering regional and

urban scale consequences (i.e., health and welfare protection).

A few points summarizing ``interacting scales'' and ``regionality''

should be considered in air management practices:

--Air quality modeling and historical monitoring trends have shown that

local air management practices have the greatest influence on near

field concentration impacts.

--Analyses of observations in the Eastern U.S. reveal the existence of

very broad multistate regions (interacting scales approaching linear

scales of 1000 km or more) of elevated pollutant levels and zones of

influence (Rao, 1996).

--Air quality modeling data for the East suggest that similar regions

of influence exist for ozone and fine particles (Dennis, 1996),

although only sparse monitoring data exist to support these

similarities.

--Modeling analyses for the Grand Canyon National Park (and other)

Class 1 areas show that fine particles and precursors causing

visibility impairment episodes are derived from both nearby (less than

50 km) and more distant (up to 1000 km) regions of influence (NRC,

1993; GCVTC, 1996).

--Area and case-specific analyses are required to delineate reasonable

geographic areas for air quality planning purposes because of the wide

regional variations in meteorology, topography and source distribution.

--The use of terms such as ``transport'' or ``background'' inadequately

describes the complex set of emissions, chemistry, meteorological

processes and interacting scales which contribute to the

regionalization of air pollution.

[[Page 65767]]

--Because of broad spatial extents and gradations of interacting scales

ranging from regional down to sub-grid cell scales, an air quality

assessment focusing on a particular scale (e.g., urban) must consider

effects due to interactions across various space and time scales. The

concept of a single MSA/CMSA nonattainment area may be inconsistent

with the spatial and temporal scales for ozone, fine particles and haze

problems.

B. Technical Basis and Considerations for Integrating Ozone, Fine

Particles and Regional Haze Implementation Programs

The technical and scientific rationale for underlying the

integration of ozone, fine particles and regional haze air quality

management practices is based on a mix of empirical observations,

atmospheric processes and practical administrative concerns. While this

discussion focuses on common attributes across pollutant groups, it is

important to recognize and distinguish those attributes where there is

little linkage. Many examples and inferences presented here tend to

reflect what is known about Eastern U.S. air quality issues (e.g.,

ozone) with possibly little relation to Western U.S. phenomena. At the

risk of generalizing (and simplifying) air quality descriptions for

illustrative purposes, recognition that a generalized approach cannot

operate effectively everywhere must be retained. The discussion focuses

on the relationship between ozone and fine particles, with the implicit

assumption that fine particle levels and chemical composition directly

relate to regional visibility impairment, given the strong relationship

between the constituents of fine particles and the manmade portion of

visibility impairment. Regional haze is a widespread, largely uniform

impairment of visibility in every direction over a large area, mostly

due to light scattering from fine particles from multiple sources.

1. Empirical Evidence for Integration

Ozone and PM-10 (particles with an aerodynamic diameter less than

or equal to a nominal 10 micrometers) concentrations in the Eastern

U.S. can exhibit similar spatial patterns during summer time episodes

(Northeast States for Coordinated Air Use Management (NESCAUM), 1995).

Analyses of PM data consistently indicate that fine particles

constitute the majority mass fraction of PM-10 in the summertime East

(EPA, 1996). In combination, these observations qualitatively imply

concurrence of elevated ozone and fine particles. However,

quantification of the similarity and frequency of such events is

severely restricted by a lack of a fine particles data base in the

East. While more data exist in certain Western locations, the episodic

relationships between ozone and PM appears to be more complex than in

the East. For example, a major component of the fine particle problem

in Los Angeles (as well as the San Joaquin Valley, Salt Lake City and

Denver) is wintertime formation of ammonium nitrate, which is not

stable at the high temperatures associated with elevated ozone. High

levels of fine particles in Western nonattainment areas can impair

visibility when high ozone concentrations are not observed.

Nevertheless, ``smog'' events in Los Angeles are almost always

accompanied by impaired visibility, and visibility is directly

associated with fine particle levels. Although some limited empirical

evidence is highly suggestive of area specific concurrent events, other

considerations as described below provide a stronger rationale for the

appropriate level of integration across ozone, fine particles and

regional haze control programs.

2. Emissions and Atmospheric Process Linkages Across Ozone, Fine

Particles and Regional Haze

Several connections exist among ozone, PM and the resulting effect

of visibility impairment. The linkages are based on the existence of

common emission precursors, source categories and atmospheric chemistry

and meteorological processes which affect more than one pollutant. For

example, emissions of oxides of nitrogen (NOX) potentially can

lead to both ozone and fine particle formation. A combustion source

often emits both SO2 (a fine particle precursor) and NOX (an

ozone precursor). The sequence of atmospheric chemistry reactions

underlying ozone formation is in part responsible for fine particle

formation. Similar meteorological processes affect the movement, mixing

and removal of ozone, fine particles and precursors. Some of these

connections are complicated and will be explained more completely in

forthcoming FACA science documents. The following are very brief

descriptions of the connections across pollutant categories.

--Common ``direct'' precursor emissions. Emissions of NOX, VOC and

carbon monoxide (CO) are considered precursors for ozone formation. The

NOX, VOC and sulfur (SOX, mostly as SO2) emissions can

also lead to fine particle formation through ``secondary'' atmospheric

chemical reactions. Both ozone and a substantial fraction (which can

vary greatly with season and location) of fine particles are the result

of secondary formation processes. The major components (which also are

highly variant) of secondary fine particles include sulfates, carbon

(elemental and organic) and nitrates. The fraction of fine particles

due to secondary processes is highly variant in space and time. During

certain conditions (e.g., available ammonia, negligible sulfate, low

temperatures), NOX emissions can lead to fine PM ammonium nitrate

formation. Several directly-emitted organic compounds contribute to

fine particle organic aerosols. These organic compounds may contribute

as ``primary'' organic aerosols, that is, they almost immediately

condense to the aerosol phase during the emissions process or shortly

downstream. Or, certain VOC (e.g., toluene) which exist as gases under

most conditions can undergo atmospheric reactions and transform into

condensible ``secondary'' organic aerosols. Thus, a VOC like toluene

can contribute to both ozone or fine particle formation as a precursor

emission.

--Common source categories. Based on the multiple roles of precursors,

a particular source (natural or anthropogenic) emitting one precursor

(e.g., NOX or VOC) can affect ozone and fine particles, and a

single source emitting multiple precursors (e.g., combustion process

releasing NOX, VOC, CO and SOX) can affect multiple pollutant

source categories. In this case, integration is not dependent on

atmospheric chemical linkages. This commonality among sources should

lead to a more consistent approach in estimating emissions of multiple

precursors within a specific source category. For instance, a

consistent approach needs to be applied for estimating and projecting

both NOX and SOX emissions from a combustion source.

--Interaction of atmospheric chemistry reaction cycles and ``indirect''

precursors. Much of the general atmospheric chemistry involved in ozone

formation can affect fine particle formation, as alluded to above, in

certain instances. For example, ozone is the major initiator of

hydroxyl radicals, a chemical intermediate which converts SO2 and

nitrogen dioxide (NO2) to more oxidized sulfate (e.g., sulfuric

acid) and nitrate (nitric acid) forms. Both sulfates and nitrates can

contribute to fine particle formation. Clearly, a linkage between ozone

and fine

[[Page 65768]]

particles exists through the role of ozone in generating hydroxyl

radicals. Note that this linkage between ozone and fine particles is at

the process level and does not require coexisting ``high'' ozone and

fine particle levels. Many other important linkages involving oxidizing

chemical species (radicals and peroxides) exist within the NOX,

VOC, SOX, ozone chemistry system. A correct characterization of

the basic ozone chemistry and the associated linkages among the

precursors is needed to predict the affect of changing emissions on air

quality indices. Consequently, the predictive air quality models used

to assess ozone and fine particle impacts should include a basic core

set of atmospheric chemical reactions (i.e., a gas phase ozone

chemistry mechanism).

Because of their common atmospheric chemical linkages, many

precursors associated with one pollutant might be considered as an

``indirect'' precursor for another pollutant as well. Virtually all

precursor emissions (NOX, SOX, VOC, CO) undergo initial

attack by hydroxyl radicals and participate in the general cycling of

various chemical intermediate species. Therefore, precursors that

typically may not be associated with a particular secondary pollutant,

such as the effect of VOC on either sulfate or nitrate, indirectly

participate through their roles in atmospheric chemistry. In this

general context, the term precursor does not imply a positive effect on

an associated secondary species as the emission precursor may only

share in certain atmospheric chemical processes without leading to

increases in a secondary pollutant. Multiple possibilities exist. For

example, NOX, which affects the cycling of hydroxyl radicals

(which convert SOX to sulfate), could act indirectly as a sulfate

particle precursor. The majority of VOC species that do not transform

into organic aerosols could nevertheless be fine particle precursors

through their general role (i.e., cycling of radicals) in atmospheric

chemistry. Nitrogen oxides could serve as indirect precursors for

aerosol sulfate formation. This ``universal'' pool of precursors does

not imply that reductions of any specific precursor lead to reductions

of every pollutant. Just as reductions in NOX potentially can

raise local ozone levels, a reduction of a fine particle precursor

possibly can increase ozone or increase a different fine particle

component (e.g., SOX reductions leading to increased ammonium

nitrate, or NOX reductions increasing sulfate formation). These

examples are some of several conceivable indirect precursor

relationships. Many other relationships with similarly unknown degrees

of effect exist. Thus, integrated implementation is far from a

straightforward exercise. Complex air quality simulation models (in

combination with simpler models and receptor/observational methods)

which include approximations of these process linkages will need to be

exercised to account for the multiple nonlinearities and positive and

negative feedbacks. This complexity demands that high quality emission

inventories, technically credible models, and spatially and temporally

representative monitoring data will be needed in predicting pollutant

concentrations and control strategies.

3. Integrating Control Strategy Development Through an Air Quality

Modeling Approach

What does integration mean from an implementation perspective?

Given the complex mechanisms for and linkages between ozone and fine

particle formation, the formulation of control strategies should

acknowledge the need to optimize control options; control of one

precursor might affect both ozone and fine particles or might be

detrimental for one or both. For example, one might start with ozone

management strategies being developed as part of ongoing urban and

regional planning efforts and attempt to quantify the future impact on

secondary aerosols. On the other hand, because NOX controls might

increase ozone levels in certain localized urban areas or because

SO2 reductions might lead to increased concentrations, efficient

air quality management would attempt to optimize the system in relation

to VOC, NOX and SOX emission reductions.

The real benefit of integration is the prospect of a more

systematic, efficient and comprehensive treatment of emission

inventories, episode selection, and atmospheric physics and chemistry

that might empower the air quality manager to characterize source-to-

receptor effects in an orderly way. The addition of data on the costs

and effectiveness of control options would enable the air quality

manager to identify the cost-effective means for attaining a variety of

air quality goals.

To this end, emission bases underlying most current ozone modeling

efforts include most of the sources for aerosol formation (but not

necessarily the aerosol-specific emissions such as organic aerosols

from motor vehicles). Notable exceptions include emissions from many of

the fugitive primary particle sources and most sources of ammonia. The

result of this hypothetical exercise could produce the residual

aerosol- (and regional haze-) related air quality benefits from an

ozone precursor control perspective. [Additional analysis directed at

the specific needs for meeting fine particle and visibility concerns

could follow this ozone oriented approach. Ideally, an objective (and

likely iterative) ability to assess the benefits and tradeoffs

associated with managing all three pollutant categories would evolve.]

Although this example does not represent ``full'' integration given the

unidirectional information flow (ozone to particles), it does

acknowledge similarities among programs and avoids mistakes and

inefficiencies incurred from independent analyses. Aside from any

direct regulatory policy, the linkages across pollutants and emissions

are reasons by themselves for planning for more effective and efficient

development and use of emissions, air quality models and monitoring

networks which address sometimes confounding multiple pollutants and

their related health/welfare effects, and control options.

4. Distinctions Among Ozone, Fine Particles and Regional Haze

Concurrent ozone and fine particle episodes may be expected to

occur given similarities in the meteorological and atmospheric

chemistry processes underlying ozone and fine particle formation,

maintenance and destruction. As discussed above, the linkages

associated with emission source categories and physical and chemical

processes exist more frequently than the occurrence of coepisodic

events. For example, several basic atmospheric chemical reactions

involved in ozone and fine particle formation occur whether or not high

ozone and fine particle levels are generated in the atmosphere.

Nevertheless, several distinctions among the pollutants persist. These

differences include the contribution of primary particles to total fine

particles (and especially PM-10) and wintertime (actually

nonsummertime) fine particle events. Some primary particles are

generated by strong wind conditions (e.g., soil/geologic material) and

other mechanical processes (e.g., roadway fugitives). A fraction of

primary PM peaks in summer in most of the Western third of the country

where there is little precipitation for 6-8 months per year, and dry,

windy conditions lead to the generation and movement of geologic

materials. As discussed earlier, ammonium nitrate, a significant fine

[[Page 65769]]

particle component in the West, is stable at relatively low wintertime

temperatures and therefore does not form significant levels during the

high summertime temperatures. Meteorological effects which influence

the creation, maintenance or removal of high levels of ozone and fine

particles may be significantly different between pollutants, regions of

the country, and times of the year. Other specific emissions-driven

events such as forest burning and wintertime woodsmoke (a major

wintertime source of urban PM) bear virtually no relation to ozone.

Many of these PM episodes can be dominated by either primary or

secondary fine particle components, or by primary anthropogenic coarse

PM emissions. Research exploring the frequency and characterization of

coepisodic and uni-episodic events would yield further insight into

underlying causes of events and provide direction for integrated

implementation opportunities.

Visibility protection presents several additional considerations

beyond the scope of topics covered under ozone and fine particles.

First, fine particle concentrations that are far below any potential

NAAQS can adversely affect visibility in a significant manner,

particularly in more pristine environments, such as Federal Class I

areas in the rural West. For this reason, visibility management needs

to consider the protection of ``clean'' days separately from

assessments focusing on highly impaired days. The meteorology and

emissions characteristics during ``clean'' days differ from those

common during high pollution episodes. This concern raises complex

technical issues related to the ability of models and monitoring

instruments, which often have been designed or tested for meeting

``high'' concentration requirements, to characterize ``low'' level

conditions. Second, relative humidity plays a significant role in

enhancing visibility impairment, particularly in the East. In humid

conditions, particularly above 70 percent relative humidity, sulfates,

nitrates, and certain organics readily take on water and expand to

sizes comparable to the wavelength of light. Particles in this size

range (e.g., 0.1 to 1.0 micron in diameter) are efficient scatterers of

light. Third, unlike the NAAQS approach of setting a national standard,

the regional haze program has as its goal the prevention of any future,

and the remedying of any existing, impairment of visibility in

mandatory Federal Class I areas which impairment results from manmade

air pollution. States are required to make ``reasonable progress''

toward this goal. The notion of background versus manmade air pollution

raises several technical and policy challenges, particularly in the

protection of visibility in ``cleaner'' environments, where small

increases of fine particles can lead to significant visibility changes.

Generally, PM-10 is not considered in the integration discussions

of ozone, fine particles and regional haze. This is because the coarse

fraction (e.g., greater than 2.5 micron) typically is derived from

primary emissions (e.g., fugitives and geologic material) with little

association to ozone from a process (or episodic) perspective. In

addition, visibility impairment leading to regional haze is

overwhelmingly associated with the fine particle fraction of PM-10.

C. Major Technical Issues

The principal technical issues associated with integrated air

quality management involve the adequacy of data bases and models

(including specific process formulations) on which to base credible

assessments. Generally, the tools (ambient data, models and emissions

data) underlying ozone analyses are better developed than those for

fine particles. Major efforts in chemical mechanism development,

ambient monitoring methods and establishment of national and special

study efforts for monitoring, emissions and modeling have resulted in a

wealth of information and familiarity with these tools. This relative

abundance of knowledge for ozone should not be construed as a science

lacking uncertainty as significant technical issues remain (e.g., the

current North American Research Strategies for Tropospheric Ozone

(NARSTO) effort) and even more are yet to be defined. A sampling of

these issues include the representativeness of emission inventories,

particularly biogenic emissions; uncertainties in the modeling system

(e.g., chemical characterizations of aromatics and biogenics, treatment

of vertical mixing processes); difficulties in monitoring techniques

(carbonyls, NOX-NO2, polar VOC); and lack of measurements

(e.g., total reactive nitrogen, upper air data). In some cases, these

gaps are significant and could compromise our ability to perform highly

credible ozone analyses and to ascribe confidence levels in our

results.

Consideration of fine particles and regional haze presents several

additional issues which are a result of: (1) A very complex multiphase,

multicomponent, multiseason aerosol system; (2) the complex covariance

of these data; and 3) the present PM-10 form of the NAAQS which has

resulted in few regulatory needs to hasten an improved

characterization. Significant concerns include major positive and

negative measurement artifacts (related to gas-particle phase changes);

a simple lack of ambient data, especially urban fine particle

measurements; poor quality assurance/control of ambient sampler data;

emissions data with poor general spatial applicability; limited

availability, limited application and evaluation of regionally-accurate

air quality models; and highly empirical treatment of organic aerosols

within the available models. These gaps are interconnected in the sense

that quality model evaluation and improvement rely on available quality

measurements. The issue is further complicated by difficulties (due to

complexities, lack of precedence and resource constraints) in designing

a data collection program to evaluate a gridded model's ability to

characterize fine particles covering wide scales of time (annual,

seasonal, daily) and spatial resolution (regional, urban, local). On

the positive side, a strong history of using ambient data for PM source

apportionment is probably more adaptable to fine particle analyses than

ozone, given that the measurable components of secondary fine particles

(e.g., sulfate) have some direct linkage to precursors, whereas an

ozone measurement by itself provides no inference regarding

contributing precursors.

Several interesting atmospheric chemistry questions remain to be

answered; two examples include nitrate fine particle formation and

organic aerosols. Where and when do ammonia and sulfate become limiting

factors in ammonium nitrate formation? The relatively abundant nitrate

fine particles at sites in the urban West contrast with abundant

regional sulfate fine particles in the East. Substantive decreases in

SO2 emissions could lead to increased nitrate fine particle

formation in the East if sufficient ammonia (a highly uncertain

emissions category) is available. What impacts will NOX emission

reductions have on fine particles? Many possibilities exist. If nitrate

is significant, one would expect a reduction in fine particles.

However, if sufficient sulfur remains available, NOX reductions

could increase or decrease sulfate formation (and, therefore, fine

particles) depending on a complex cycling of oxidizing species.

Reductions in NOX emissions could actually lead to sulfate

increases by reducing competition (between SOX and NOX) for

gas phase oxidizing radicals, or by increasing peroxide levels leading

to

[[Page 65770]]

greater aqueous phase sulfate production. Or, NOX reductions could

slow down sulfate formation through overall reductions in ozone and

other oxidants. This relationship is very complex, and we must exercise

caution in associating fine particle benefits with NOX reductions

in the Eastern U.S.

What are the relative contributions of primary and secondary

organic aerosols across varying spatial (and time) scales? The

potential for large secondary organic aerosol production from biogenic

sources (e.g., pinene emissions) exists throughout the East. How

significant are biogenic-derived aerosols compared to local/urban

contributions from primary anthropogenic organic aerosols? How

different are these relative contributions across seasons, given that

secondary organic aerosol formation increases during the summer? Many

uncertainties underlie the integration of primary and secondary

particles, aside from integrating particles and ozone. For instance,

what are the interactive roles exerted by elemental carbon emissions

and other products of incomplete combustion and geologic materials in

both primary contribution to PM and as formation nuclei for highly

complex secondary PM? On balance, the ability to perform ozone air

quality assessments far exceeds that of fine particles. However, the

infrastructure for conducting fine particle analyses appears to be in

place as a result of progress gained from ozone and acid deposition

modeling and existing monitoring programs for ozone and visibility

(i.e., the Interagency Monitoring of Protected Visual Environments

(IMPROVE) program). Finally, although uncertainties remain in

transforming particles into visibility impairment within short

averaging times, the IMPROVE methodologies for particle and visibility

measurements (and the relationships between particles and visibility)

are widely accepted.

Specific issues across PM and ozone include the ability to

formulate fully-integrated models accounting for multidirectional

effects on several pollutants. For example, the formation of secondary

organic aerosols is a loss mechanism for VOC which presently is not

accounted for in ozone modeling efforts. Many other integration topics

exist, and collectively there is uncertainty regarding the overall

importance of one pollutant imparting an effect on another.

Two basic issues span the gap between science and policy: (1) The

manner in which tools are applied, and (2) accommodating scientific

findings and uncertainties in air quality management decision making.

The first topic reflects the concerns of how one applies deterministic

(i.e., models that establish exact cause and effect relationships) and

uncertain air quality models to probabilistic forms of the standard in

ascribing rigid control requirements. The selection of ``severe''

meteorological episodes versus ``prototypical'' episodes for ozone and

PM-10 modeling has been controversial and remains a difficult model

application issue. Equally complicated is the emerging need to model

seasonal and annual cases. The debate on the credibility of models is

fueled by the manner in which they are applied as much as by concerns

about their formulations and supporting data bases. The second topic

acknowledges the need for conducting policy-relevant as opposed to

policy-driven research and recognizing the different time scales

operating in research and policy arenas (where the timeframe demands

move much faster than research results). Extremely useful information

emerges continuously from research programs, yet a separate, sometimes

very significant, time-lag occurs before information is considered in

the policy-setting process. Hence, opportunities must be available to

incorporate the latest science into policy.

D. Integrating Models and Observations for Sound Air Quality Management

Practice

Much emphasis has been placed on the complementary and integrated

use of models and ambient data in air quality management practice (Rao

et al., 1996). Several facets are associated with this topic, ranging

from the need to evaluate models with sound data bases to conducting

fully integrated analysis optimized through the separate, strong

attributes of data and models. As the technical debate on the use of

models and data continues to mature, perceptions such as ``model'' or

``data'' are replaced by the intelligent and integrated use of ``models

and data.'' Clearly, the demand for measurements initiated by the

National Academy of Sciences Ozone Report (NRC, 1991) to provide

feedback information loops, as well as empirically-based corroboration

of predictive tools, has been adopted by large segments of the air

quality community and reflected in major efforts such as the

Photochemical Assessments Measurement Stations (PAMS) and NARSTO.

An appreciation of the strengths of models and observations can

assist the understanding of current analyses and lead to improved

techniques. A model's strength is its ability to: (1) Integrate an

enormous spectrum of data (e.g., emissions and meteorological

variables) and process understandings (e.g., chemical mechanisms and

flow phenomena), and (2) serve as an exceptional space and time mapping

tool. This latter attribute reflects the model's unique ability to

predict into the future and to supplement (or fill in) present gaps in

observed data. The process formulations embedded in models enable the

addressing of many ``what if'' questions related to emissions control.

However, models are engineering tools that invoke substantial

approximations of scientific understandings of natural phenomena, both

their formulations and application methods reflect engineering

principles more than fundamental science. Observations provide a basis

for testing and diagnosing models. Also, in some instances,

observations add another benefit. They can capture process-type

relationships by themselves (e.g., the emergence of observational-based

models for defining NOX and VOC control preferences). However,

often observations are very sparse.

Applied in isolation, the use of either models or observations

alone is not desirable. Space and time constraints often bias the

interpretation of observational analyses (i.e., analysis results

reflect time and space of monitors which may or may not reflect the

scales of concern). Models suffer from a very large spectrum of

weaknesses because they attempt to portray so many phenomena. Most

critical though is the risk of using a potentially biased model that is

assumed bias free. The integrated use of observations and models

mitigates the individual weaknesses of both approaches and produces a

powerful air quality management tool, especially when applied in an

iterative (even retrospective) manner to continually assess model

results and related implementation strategies.

E. Summary

Air quality assessments for fine particles, ozone, and regional

haze must consider emissions, meteorological processes, atmospheric

chemistry, and deposition, all of which interact over multiple spatial

and temporal scales. Examining in detail the sources only from the MSA/

CMSA surrounding the monitor reporting nonattainment levels of air

quality may need to be augmented (on a space and time basis) for

responsibly allocating those levels to the sources causing them. When

examining the issues on expanded time and space scales, the air quality

management should also take into account the similarities of these air

quality indices,

[[Page 65771]]

such as their common precursor emissions (e.g., NOX, VOC); common

emissions sources (e.g., mobile sources, stationary and area source

combustion emissions, biogenics); and shared chemical and

meteorological processes (e.g., transport, transformation,

precipitation, and removal).

The principal technical issues associated with integrated air

quality management involve the adequacy of data bases and models

(including specific-process formulations) on which to base credible

assessments. Many of these gaps are interconnected since model

evaluations rely on available high quality measurements of emissions,

atmospheric processes (such as wind fields) and ambient concentrations.

On balance, the ability to perform ozone air quality assessments far

exceeds that of fine particles, due mostly to the development of ozone

research as well as a lack of urban fine particle measurements and

important emissions components. However, many of the components of the

infrastructure for conducting fine particle analyses appears to be in

place as a result of progress gained from ozone, acid deposition, and

visibility modeling and monitoring programs. The integrated application

of models and observed data is strongly encouraged. In combination,

both approaches help to mitigate the weakness of an isolated approach,

producing a powerful tool for air quality management.

III. Schedules

Both the ozone NAAQS notice of proposed rulemaking (NPR) and the PM

NAAQS NPR are expected to be published in December 1996 with

promulgation of both the PM and ozone NAAQS scheduled for mid-1997. The

previously-described IIP will be proposed for comment in late 1996 and

finalized in mid-1997 and will apply during the time period following

promulgation of any revised NAAQS. The ozone, PM and regional haze

programs are tentatively planned to be developed on a common schedule.

As indicated above, the integrated implementation strategy for

ozone and PM NAAQS will be issued in two phases. The Phase I

implementation strategy which will give guidance to State and local

agencies concerning actions prior to and including designation of areas

not attaining potential new PM and ozone NAAQS will be proposed in mid-

1997 with a public comment period prior to adoption of the strategy.

The EPA expects that the Subcommittee and CAAAC will make

recommendations regarding formulation of the Phase I strategy prior to

proposal. In mid-1998, the Phase I implementation strategy will be

finalized. (Note that prior to recommendations from the Subcommittee

and CAAAC, EPA will refer to areas not attaining new NAAQS as

nonattainment areas.)

Also in mid-1998, the Phase II implementation strategy will be

proposed. This strategy will provide guidance for the events and

actions between area designation and submittal and approval of State

implementation plans (SIP's). This will include control strategies. The

EPA expects that the Subcommittee and the CAAAC will also make

recommendations regarding formulation of the Phase II strategy prior to

proposal. In mid-1999, the Phase II implementation strategy will be

finalized.

Unlike the NAAQS, the regional haze rule will not set a specific

ambient pollutant standard. However, the rule will include criteria for

measuring reasonable progress and the methods to measure progress. The

EPA currently intends to publish the regional haze NPR in mid-1997

(with Phase I). The EPA is exploring ways to coordinate regional haze

program implementation with NAAQS implementation.

IV. Framing of Phase I Implementation Issues

The Phase I issues below were identified by EPA with substantial

input from the Subcommittee and represent the priority issues which

must be addressed as soon as possible after the revision of the NAAQS.

These issues and options are subject to change as the FACA process and

deliberations continue. The options/principles/questions which are

presented are not all inclusive and are designed to stimulate public

discussion. These options/principles/questions are not intended to

indicate preference or represent any decisions and are under active

FACA consideration. Consistent with the broad mandate given to the

Subcommittee, the EPA is actively seeking new ways to implement the

potential revised ozone and PM NAAQS and regional haze programs, and at

this time is not evaluating legal constraints in the Clean Air Act

(Act) which may limit or change some policy options identified below.

For example, revision of an ozone or PM NAAQS will require EPA to

determine the effect of the new planning requirements triggered by the

revised NAAQS on the existing planning requirements in the various

subparts of part D of title I of the Act. The EPA is not addressing

such legal issues in this notice. The purpose of this advance notice is

to stimulate public interest and comments on a wide range of policy

issues and options, without limitation at this stage, from legal

constraints. After the FACA process produces policy options and

recommendations and as the EPA develops a proposed and final integrated

implementation strategy, the EPA will consider legal authorities and

constraints which may be present in the current Act.

The issues identified below regarding implementation of a potential

ozone or PM NAAQS revision generally use as their frame of reference

the basic planning requirements of part A of title I of the Act and the

basic nonattainment planning requirements of subpart 1 of part D of

title I of the Act. Similarly, the discussion below addressing

development of a regional haze program does not analyze pertinent legal

issues but endeavors to use as a general frame of reference the

visibility protection provisions in sections 169A and 169B of the

current Act. Rather than focusing on the statutory requirements,

however, the following discussion identifies technical and policy

issues and options under consideration. Again, interested readers are

directed to the EPA TTN and WWW site for an up-to-date status of FACA

deliberations on these issues. The EPA is including the issues with

sufficient background information in this ANPR to allow interested

individuals to comment on the development of the implementation

strategies.

Upon a proposal to revise current NAAQS or promulgate new NAAQS for

ozone and PM and regulations for regional haze, the following

characterize the most important implementation issues identified so far

that should be considered. The issues are divided into two phases of

implementation development. The options/principles/ questions are

presented as a broad range of possibilities and are not listed in any

order of preference.

A. Phase I Issues

1. Regional Haze Program Development

In order to place the following discussions on the issues

associated with joint programs in the proper perspective, this section

begins with a discussion of issues and questions related to the

development of a regional haze program. As described in section II,

regional haze is produced by emissions of fine particles and their

precursors from a multitude of manmade and natural sources located

across a broad geographic area. Fine particles impair visibility by

scattering and absorbing light. Average visual range in most of the

Western U.S. is

[[Page 65772]]

100-150 km. In most of the East, the average visual range is less than

35 km. The following discussion includes general background on the

existing visibility protection program, recommendations to EPA for

improving regional haze conditions, and key issues for consideration in

a new regional haze program.

Under a national visibility goal that calls for the prevention of

any future, and the remedying of any existing, impairment of visibility

in mandatory Federal Class I areas which impairment results from

manmade air pollution, the EPA's 1980 visibility regulations addressed

local visibility impairment that was ``reasonably attributable'' to a

single source or small group of nearby sources. Under these rules, the

36 States containing mandatory Federal Class I areas were required to:

(1) develop a program to assess and remedy visibility impairment from

new and existing sources, (2) develop a long-term strategy to assure

progress toward the national goal, (3) develop a visibility monitoring

strategy, (4) consider ``integral vistas'' outside of Federal Class I

areas in all aspects of visibility protection, and (5) notify Federal

land managers (FLM) of proposed new major stationary sources and

consider visibility analyses conducted by FLM in their permitting

decisions.

The 1980 rules were designed to be the first phase in EPA's overall

program to protect visibility. The EPA explicitly deferred action

addressing impairment from regional haze due to the need for further

research and improvements in several technical areas, including

visibility monitoring, modeling, and the relationship between specific

emitted pollutants and visibility impairment. The GCVTC was established

to assess scientific and technical information regarding adverse

impacts on visibility in the transport region and provide

recommendations to the EPA for addressing these adverse impacts. Within

18 months of receipt of the GCVTC recommendations, the Administrator is

required to carry out her ``regulatory responsibilities under section

169A, including criteria for measuring 'reasonable progress' toward the

national goal.'' In developing the regional haze program, EPA will also

have the benefit of recommendations from the 1993 report of the NRC

Committee on Haze in National Parks and Wilderness Areas, Protecting

Visibility in National Parks and Wilderness Areas, and from the work of

the FACA Subcommittee on Ozone, PM and Regional Haze Implementation

Programs. The following addresses key issues for consideration in

developing a regional haze program.

Issue: Applicability--Currently, States containing mandatory

Federal Class I areas where visibility has been identified as an

important value, or having sources which may reasonably be anticipated

to cause or contribute to any impairment of visibility in any such

area, must revise their SIP's to make reasonable progress toward the

national visibility goal. Existing visibility regulations apply to the

36 States containing one or more mandatory Federal Class I areas.

Studies have shown that regional haze can be caused by fine particles

that are transported hundreds or even thousands of kilometers. Thus,

sources in States having no mandatory Federal Class I areas could

potentially contribute to impairment in Federal Class I areas in other

States. The regional haze program should address the potential

applicability to all States.

Issue: Regional Haze Planning Areas--It has been recognized in many

forums that programs to mitigate regional haze may require multistate

or regional approaches to technical assessment, planning, and/or

control strategy implementation. Potential regional approaches are

currently under discussion through the FACA process. Key questions to

be considered are: (a) if regional approaches are taken, should one set

of multistate groupings be developed to address ozone, PM, and regional

haze implementation programs, or should separate approaches be taken

for each of the three programs; and (b) should existing or new

institutions be responsible for future planning activities related to

these three programs?

Issue: Definition of Reasonable Progress--The term ``reasonable

progress'' was not specifically defined in the 1980 visibility

regulations for purposes of regional haze. Current regulations require

SIP's to contain such emission limits, schedules of compliance and

other measures as may be necessary to make reasonable progress toward

the national goal, including: (1) requirements for best available

retrofit technology (BART) for certain major sources of pollution, and

(2) a long-term strategy for making reasonable progress toward meeting

the national goal.

In the June 1996 report from the GCVTC, the Public Advisory

Committee defines reasonable progress as ``achieving continuous

emission reductions necessary to reduce existing impairment and attain

steady improvement in visibility in mandatory Federal Class I areas,

and managing emissions growth so as to prevent perceptible degradation

of clean air days.'' In the GCVTC report, visibility impairment is

defined in terms of total light extinction and deciview. The

legislative history of the 1990 Amendments to the Act also addresses

the issue of reasonable progress and perceptible improvement. Senator

Adams, the sponsor of the 1990 revisions to the visibility protection

program stated that, ``At a minimum, progress and improvement must

require that visibility be perceptibly improved compared to periods of

impairment, and that it not be degraded or impaired during conditions

that historically contribute to relatively unimpaired visibility.''

Question: What should be the criteria for measuring reasonable

progress?

The assessment of reasonable progress can involve quantitative and

nonquantitative factors. From a quantitative perspective, measurement

of reasonable progress could incorporate assessments of visibility

trends, emission reductions, or a combination of both. Tracking

visibility trends suggests a periodic assessment of visibility

conditions (e.g., averages of 20 percent best and worst days, annual

average) as derived from visibility monitoring data and use of a common

metric nationally. The light extinction coefficient would be a logical

choice since it has been used widely for years and is routinely

calculated from optical and aerosol measurements for all IMPROVE sites.

Tracking progress will also require the initial documentation of a

baseline level of anthropogenic visibility impairment at mandatory

Federal Class I areas. The GCVTC has recommended an emission reduction

target approach, including review of compliance with an SO2

percent emission reduction target in the year 2000 and 5-year progress

reviews thereafter. Nonquantitative progress factors could address

whether a State has taken certain administrative or technical actions

determined necessary for measuring and achieving progress over time.

Other questions related to reasonable progress include:

Question: How frequently should progress be measured?

Question: Since monitors are located at only about one-quarter of

the 156 mandatory Federal Class I areas, how can progress be

demonstrated for sites without monitoring?

Question: Should reasonable progress be demonstrated on a

``regional'' basis (i.e., for groups of Federal Class I areas), with

certain IMPROVE sites deemed

[[Page 65773]]

representative of others lacking monitoring?

Question: Would tracking of emissions reductions and conducting

regional modeling be an acceptable surrogate to using monitoring data?

Question: Would the GCVTC approach, which specifies maintaining

(rather than improving) average ``clean day'' conditions, be

appropriate for areas with higher levels of anthropogenic pollution and

thus greater room for improvement (such as most of the Eastern U.S. and

selected areas in the West)?

Question: How should a reasonable progress determination take into

account the degree of improvement in visibility which may reasonably be

anticipated, the costs of compliance, the time necessary for

compliance, and the energy and nonair quality environmental impacts of

compliance, and the remaining useful life of any existing source

subject to such requirements?

Question: What should be required in a State's long-term strategy

for making reasonable progress under the regional haze program?

One element of the reasonable progress demonstration should

describe the State's strategies for preventing future impairment and

ensuring continued progress for a long-term strategy. Estimates of

future population growth and associated changes in emissions, and a

plan to ensure reasonable progress under these anticipated conditions,

could be required by the program. Current visibility regulations

require States to revise their long-term strategies every 3 years with

respect to reasonably attributable impairment. A regional haze program

should address long-term strategies for mitigating all types of

visibility impairment, including regional haze impacts.

Another consideration is the implementation of current statutory

requirements. An EPA Report to Congress dealing with the effects of the

1990 Act Amendments on visibility in Class I areas estimated that Class

I areas from Maine to Georgia would see perceptible improvements in

summer and winter visibility under expected implementation of the

Amendments. The most significant improvements are expected for Class I

areas along the Central and Southern portions of the Appalachian

Mountains. The 1993 report indicates that modeled future improvements

in annual average Eastern regional visibility are directly related to

expected reductions of SO2 emissions under title IV of the Act

(i.e., the acid rain program). Note, however, that current models are

not reliable enough to estimate the extent of improvement in the number

of clear and hazy days at specific locations.

Question: How should regional haze regulations address the

requirement for BART for sources that may reasonably be anticipated to

contribute to regional haze?

Rules for regional haze are required to address BART for any major

source placed in operation between 1962 and 1977 that ``emits any air

pollutant which may reasonably be anticipated to cause or contribute to

any impairment of visibility'' in a mandatory Federal Class I area. The

EPA's current visibility rules limit BART to major stationary sources

whose contribution is ``reasonably attributable'' to impairment in a

Federal Class I area. Recognizing that determinations of BART for

regional haze involves contributions from multiple sources, EPA

solicits comment on how technological controls, costs, the degree of

improvement in visibility which may reasonably be anticipated, and

other factors contained in section 169A(g)(2) should be considered.

Section 169A(g)(2) defines BART as follows: ``* * * in determining

best available retrofit technology, the State (or the Administrator in

determining emission limitations which reflect such technology) shall

take into consideration the costs of compliance, the energy and nonair

quality environmental impacts of compliance, any existing pollution

control technology in use at the source, the remaining useful life of

the source, and the degree of improvement in visibility which may

reasonably be anticipated to result from the use of such technology * *

*.'' (42 U.S.C. 7491(g)(2).

Under the existing visibility program, the BART process has

involved extensive technical assessments to demonstrate that emissions

from a specific major source contribute a specific amount of impairment

at a specific Federal Class I area. The regional haze program should

address whether the BART requirement would be interpreted differently

for the purposes of remedying existing impairment due to the cumulative

emissions from sources located across broad regions.

One alternative interpretation could involve the identification of

sources potentially subject to BART, development of emission rates

determined to be equivalent to BART for key source categories, the

estimation of total emission reductions that would be achieved if BART-

level emission rates are implemented, incorporation of these reductions

into regional emission reduction targets, and implementation of

programs by the States to achieve these emission reductions. Regional

emission reduction targets for BART could be met through reductions

from BART-eligible stationary sources, or the program could potentially

allow an equivalent level of reductions through some other means, such

as a trading program. Under such an approach, proposed emission

reductions planned for attaining any new NAAQS will improve visibility

conditions to some degree. Thus, program integration is needed to

assess the extent to which strategies for attaining the NAAQS will help

meet section 169A requirements for making reasonable progress and

implementing BART.

Question: What should be the process for FLM's and EPA involvement

in reviewing SIP revisions and reasonable progress demonstrations?

States are required to consult in person with the appropriate FLM's

before holding a public hearing on any SIP revisions for visibility.

The regional haze program, therefore, should define roles and

responsibilities of FLM's, States, and EPA in the review of SIP

revisions and reasonable progress demonstrations. It should include

ways that input from FLM's and EPA can be incorporated early in program

planning activities.

Issue: Visibility SIP revisions due after 12 months--States will be

required to revise their SIP's within 12 months of promulgation of

regional haze regulations.

The regional haze rules will need to identify the program elements

to be addressed in these SIP's. Monitoring strategies, emissions

inventories and tracking, emission limitations, schedules of

compliance, and adequacy of personnel, funding, and authority for

program implementation are all important areas for consideration. The

EPA seeks input on other elements that should be included in visibility

SIP's and how to coordinate regional haze program implementation with

NAAQS implementation.

Issue: Monitoring Program--Since 1987, EPA has supported the

IMPROVE network in cooperation with the National Park Service, other

FLM's, and State organizations. The IMPROVE network employs aerosol,

optical (i.e., nephelometers and transmissometers) and scene (i.e., 35

mm photography) measurements. Direct measurements are taken of fine

particles and precursors that contribute to visibility impairment at

more than 40 mandatory Federal Class I areas across the country.

Aerosol measurements are taken twice a week

[[Page 65774]]

for PM-10 and fine particle masses and for key constituents of fine

particles, such as sulfate, nitrate, organic and elemental carbon, soil

dust, and several other elements. Measurements for specific aerosol

constituents are used to calculate ``reconstructed'' aerosol light

extinction by multiplying the mass for each constituent by its

empirically-derived scattering and/or absorption efficiency. These

reconstructed light extinction levels are cross-checked with

nephelometer and/or transmissometer measurements. Knowledge of the main

constituents of a site's light extinction ``budget'' is critical for

source apportionment and control strategy development. These

methodologies allow estimates of how proposed changes in atmospheric

constituents would affect future visibility conditions.

Currently, the IMPROVE monitoring protocols for aerosol, optical,

and scene measurements are not included as Federal reference methods

because visibility is not regulated under the NAAQS. The EPA is

developing a visibility monitoring guidance document, however, that

will identify important methods and procedures for effective aerosol,

optical, and scene monitoring.

Question: Will the current IMPROVE network be sufficient to

determine reasonable progress for mandatory Federal Class I areas?

States implementing a new regional haze program can benefit from

the existing infrastructure of the IMPROVE network, established

protocols, existing sites, and historical data available. The fact that

monitoring equipment is located at only about a quarter of the 156

mandatory Federal Class I areas, however, raises the issue of whether

the current configuration is representative of all sites, and whether

the network needs expansion. The GCVTC, in its recommendations on

future technical needs, states that: ``The current IMPROVE monitoring

network only measures aerosol samples twice a week and at only a few

Federal Class I sites * * *. Consideration should be given to expanding

the coverage or redeployment of resources in the IMPROVE network to

enhance completeness of the data set, including on tribal lands. In

addition, background surveillance sites could be established at

intermediate locations between Federal Class I areas and large regional

sources (metropolitan areas) to provide a better understanding of the

intermediate course of atmospheric chemistry and transport. Monitoring

should be maintained at existing sites in order to allow for long-term

trend analysis.''

As discussed above, visibility SIP submittals and State reasonable

progress demonstrations likely will rely on monitored data from the

IMPROVE network. Thus, it should be determined whether the existing

geographic distribution of IMPROVE network sites is adequate for making

future determinations of reasonable progress in all Federal Class I

areas and for verifying models for predicting possible visibility

effects of future air quality management strategies. In addition, the

ability for the current cooperative arrangement between EPA, FLM's and

the States for managing and funding the network in the future should be

assessed.

2. Designations for New NAAQS and Regional Haze Planning Areas

Under the current statutory requirements and EPA policy, EPA is

required to designate areas as attainment, nonattainment, or

unclassifiable after promulgation of a new or revised NAAQS. The

designation process allows EPA to identify geographic regions where the

public is subject to potential health risks, to alert the public to the

existence of those areas, and to require States to establish control

programs to mitigate those health risks.

The EPA is giving advance notice that regional haze planning areas

(to address Federal Class I areas) may need to be established for the

purposes of conducting technical assessments and developing plans to

abate haze on a regional basis. This is the approach to reducing haze

recommended by the NRC, as well as the GCVTC. Because haze results from

direct emissions of fine particles and fine particle and ozone

precursors, the Subcommittee is considering whether regional haze

planning areas should coincide with nonattainment areas or other types

of control strategy areas established to reduce ozone and PM.

Given that EPA will designate areas and may establish regional haze

planning areas, there are several issues that must be resolved. These

relate mainly to the timing of designations, the basis for designations

(e.g., the use of monitoring or modeling data), the size of

nonattainment areas, and the role of transport in the designations

process. These requirements raise questions such as the following.

Question: What are EPA's options in developing designation schemes

for areas violating the new revised NAAQS?

Question: Should there be differentiation in designations between

areas where violations are occurring and the source areas contributing

to the problem?

Question: Should nonattainment status be changed to indicate only a

public health risk or should nonattainment both indicate the public

health risk and trigger control strategies?

Other questions identified to date include the following.

Question: What information should be used as a basis for

designating areas and establishing regional haze planning areas, e.g.,

monitoring data, modeling data, other data, or combinations of

monitoring, modeling, and other data?

Question: If monitoring or modeling data are relied upon, will

adequate information be available within the appropriate timeframe?

Question: To what extent, if any, should the boundaries of

nonattainment areas, control strategy areas and regional haze planning

areas coincide or should there be separate areas for ozone, PM, and

regional haze?

Question: How can incentives be created to monitor air quality in

order to gain a better scientific understanding of the pollutants and

avoid disincentives when NAAQS violations are measured? How can

incentives be created for private sectors to form monitoring

partnerships with EPA and States?

3. Mechanisms to Address Regional Strategies

Question: How do we develop or use existing institutional

mechanisms to effectively implement control strategies incorporating

multistate regionally--or nationally-applicable measures?

Reviews of monitoring/modeling data suggest that violations of new

ozone NAAQS in the center of the range described by the Clean Air

Science Advisory Committee (CASAC) are likely to be more widespread

than is the case with the current NAAQS. Further, data available at

this time suggest that if a PM-2.5 NAAQS is established in the lower

end of the range being considered, it too may result in a problem which

is regional in scope. By its definition, regional haze is a regional

problem. Areas that present the most concerns for visibility protection

(i.e., Federal Class I areas such as national parks and wilderness

areas) are often located at considerable distances from anthropogenic

sources of visibility degradation.

The likely regional scope of problems meeting new NAAQS or

visibility goals implies a need for measures applied over large (e.g.,

multistate) geographical areas.

Question: Should a framework for institutional mechanisms be

identified

[[Page 65775]]

and developed for facilitating development and implementation of

strategies to reduce regional transport of ozone, fine particles, and

their precursors?

Recently, several cooperative efforts have emerged to better

understand and address regional problems. Some of these have been

mandated, others are voluntary. Examples include NESCAUM, Mid-Atlantic

Regional Air Management Association (MARAMA), Lake Michigan Air

Directors Consortium (LADCO), OTC, Southeast States Air Regional

Management (SESARM), OTAG, Western States Air Resources Council

(WESTAR), GCVTC, State and Territorial Air Pollution Program

Administrators/Association of Local Air Pollution Control Officials

(STAPPA/ALAPCO) and the Environmental Commissioners of States

organization (ECOS).

Question: What attributes of existing multistate institutions have

been successful or appear essential for assisting in the development

and implementation of a regional strategy? Can or should multistate

institutions be developed using one or more existing institutions as a

starting point?

To identify an appropriate institutional mechanism to facilitate

State implementation of programs to meet several air quality goals

which are regional in scope, it is first necessary to more specifically

define what principles are appropriate for such a group. The following

principles, developed by the National and Regional Strategies Work

Group to guide their deliberations, are proposed for consideration.

Principle: The institutional mechanism which is established should

develop an operating protocol whereby participating States can reach

agreement on regional measures to implement. The protocol would address

such issues as, who gets to vote?; what constitutes consensus?; to what

extent are consensus decisions binding?; what should be the role of the

private sector?; what steps should be followed if there is no

compliance with an agreement?

Principle: The institutional mechanism should develop a means for

summarizing and distributing information on the scientific basis,

technical viability and capital/operating costs associated with

measures under consideration. In addition, the institution should

provide a means, along with the EPA, for facilitating distribution of

consistent information regarding emissions, air quality, meteorological

data and modeling results to member States.

Question: When considering possible regional strategies, what

limitations are imposed by State laws or other constraints? Are clear

priority options or ``operating principles'' needed for any

institutional mechanism which is formed to help implement regional

control measures? The following principles serve as possible examples.

Principle: Use the institutional mechanism as a means to establish

positive incentives for upwind areas to reduce precursor emissions.

Possible approaches to consider include: having downwind areas/sources

defray some of the control costs at upwind locations in exchange for

not having to implement the most costly controls in their area, use of

performance goals rather than specific measures, and providing a

``bonus credit'' for early implementation.

Principle: Use the institutional mechanism as a means for fostering

communication among States and the private sector involved with

implementing measures. This goal envisions the mechanism as providing

an information clearinghouse on what different States are doing and the

appropriate contacts for further details. The institutional mechanism

might also serve as the means for facilitating periodic meetings on

various subjects related to implementing regional strategies in a

coordinated fashion.

Principle: Use the institutional mechanism as a means for promoting

use of improved analytical tools and data bases as well as to promote

use of consistent assumptions among the States which are implementing

regional measures.

4. Integration of NAAQS and Regional Haze Implementation Programs

Question: When and where does it make sense to develop and

implement integrated criteria and policies for urban ozone, fine

particles and regional haze control programs?; for regional ozone, fine

particle and regional haze control programs?

As discussed in the previous science section, the photochemical

reactions involving VOC, NOX and sunlight which produce ozone also

produce other secondary pollutants. The photochemical reactions can

result in oxidation of SO2 and NOX to produce visibility-

reducing species which may be regarded as fine PM or as haze. This

realization leads to the question of whether control of ozone, fine

particles and haze can be optimized through consideration of all of

them together in an integrated fashion rather than considering each

separately. This issue considers first how to decide if integration is

appropriate and second, if it is, then what integrated control

strategies should be implemented to reduce the impact on public health

and improve visibility caused by regional haze?

Before key national/regional/multipollutant control strategies can

be developed, a clear understanding of what integration of ozone, PM,

and regional haze means to the implementation process must be

established. For instance, if the goal is to minimize the burden on the

regulated industry, then the outcome of the control strategy may look

different from one with the goal of maximizing the risk reduction to

public health and welfare. Will the knowledge and understanding of

these approaches be understood and the technical tools needed to

integrate the programs be available, or must new state-of-the-science

and technical tools be developed?

While the focus of control strategy integration centers around the

ozone, PM and regional haze programs, some consideration of how other

programs affect these programs will need to be assessed (i.e., acid

rain, climate change, stratospheric ozone, ecosystem protection,

toxics). A number of questions arise when considering the feasibility

of an integrated strategy.

Question: What should be the basis for designing control

strategies?

Question: Should integration utilize consistent or uniform modeling

approaches to understanding long-range transport? What is the most

practical way to accomplish this?

Question: Is an atmospheric chemistry linkage needed between all

the programs? Currently, efforts are under way for fine particles and

ozone. There may be some SO2 chemistry included and limited toxics

integration. Are these adequately characterized?

Question: How should multipollutant integration fit into the

development and initiation of control strategies and programs?

Question: How can contributing sources be identified?

Question: If equity between control of long-range transport and

control of local generation of pollutants is important, how could it be

defined?

Question: What qualitative considerations can be made to provide

assurance that control programs for ozone, PM, regional haze, toxics,

acid deposition, etc., are integrated with one another?

To identify an appropriate framework for implementing efficient

programs that meet several air quality goals for pollutants which are

regional in scope, it is first necessary to more specifically define

what principles are appropriate. As indicated above, the following

[[Page 65776]]

principles are guiding the National and Regional Strategies Work Group

deliberations and could provide an initial set for consideration:

Principle: Pursue integrated control strategies for simultaneously

reducing ambient concentrations of tropospheric ozone and fine PM if

there are sufficient observation-based data to demonstrate both an

environmental and economic benefit to integration.

Principle: Emphasize performance-based control strategies in lieu

of prescriptive command-and-control strategies.

Principle: Develop controls that establish emission reduction

responsibility based on the contribution to the problems, while also

considering cost-effectiveness.

Principle: Emphasize broad-scale control strategies for

contributing sources where dictated by sound science.

Principle: Focus on the interactions of the pollutants and the

interactions between control strategies, identifying both positive and

negative interactions.

Principle: Integrate the implementation of the three programs

(ozone, PM, and regional haze) to the greatest extent possible.

Principle: Recognize that decisions need to be made based on

scientific information that is improving and find institutional

mechanisms to allow for mid-course corrections when significant new

information is available.

5. Prevention of Significant Deterioration (PSD) of Air Quality and

Nonattainment New Source Review (NSR)

Protection of the NAAQS, including new and revised standards, is

provided in part under Federal regulations requiring the

preconstruction review of large new and modified stationary sources of

air pollution, referred to as ``major stationary sources.'' As

described below, the nature of the changes which EPA will be proposing

to the implementation policies for the NAAQS for both ozone and PM will

necessitate consideration of significant changes to these regulations

commensurate with the types of issues already described in this ANPR.

Two separate preconstruction review programs exist, based on the

air quality attainment status of the proposed location of source

construction. Major stationary sources locating in areas designated

attainment or unclassifiable for a particular pollutant are subject to

requirements for the PSD of air quality. Major stationary sources

located in areas designated nonattainment for a particular pollutant

must undergo review via nonattainment NSR requirements.

Under the PSD program, a major stationary source is defined as one

that emits or has the potential to emit 250 tons per year (tpy) or more

of any air pollutant, except where a source is one in a category

specifically listed as a 100 tpy major source category. In addition to

the pollutant for which the source is major, the PSD preconstruction

review applies to each regulated pollutant which the major source will

have the potential to emit in significant amounts, as defined by EPA

regulations. Sources required to undergo PSD review generally must

demonstrate to the applicable permitting authority that proposed

emissions increases will not cause or contribute to violations of the

NAAQS or maximum allowable pollutant concentration increases (known as

increments). Under certain circumstances, the source may also need to

demonstrate that emissions will not have an adverse impact on air

quality related values in Federal Class I areas. The air quality impact

analyses associated with these demonstrations rely upon the use of both

predicted (modeled) air quality and measured (ambient monitoring) data.

The predictions of air quality using air dispersion models require the

use of emissions data for the new or modified source and certain

existing sources within the potential area of impact. Where adequate

ambient data are not available, the permitting authority may require

the PSD applicant to collect 1 year of ambient monitoring data. As

described earlier in this ANPR, changes in the way which air quality

assessments are made, considering how emissions, meteorological

processes, atmospheric chemistry, and deposition occur over multiple

spacial and temporal scales, will likely affect the way in which future

PSD air quality impact analyses are carried out for ozone and PM.

In addition, the PSD applicant must demonstrate that proposed

emissions increases will be controlled through the use of best

available control technology (BACT). The determination of BACT involves

the selection of the most effective control technology for reducing

emissions of a particular pollutant on a case-by-case basis, taking

into consideration energy, environmental and economic impacts and other

costs. Decisions for controlling PM, for example, could be affected by

the particle size, as well as the chemical composition, of the PM

proposed to be emitted. Moreover, changes to the requirements for

applying BACT to individual sources may be needed to more adequately

address the consideration of precursor contributions and atmospheric

chemistry in selecting the best controls to provide the most effective

ambient benefits for ozone and PM.

Increments for PM were originally defined for total suspended

particulate (TSP). The EPA later replaced those increments with PM-10

increments following replacement of the TSP NAAQS with the PM-10 NAAQS.

Should EPA adopt NAAQS for PM which include standards for both PM-10

and fine particles, then EPA will need to consider how that will affect

the current PM-10 increments. Increments for ozone have never been

established because of the technical difficulty associated with

predicting ambient concentration changes resulting from individual

stationary sources of VOC.

Under the nonattainment NSR regulations, ``major source'' is

defined generally as any stationary source that emits, or has the

potential to emit, in consideration of controls, 100 tpy or more of the

nonattainment pollutant, except in specific cases where lower

thresholds apply to more serious nonattainment classifications. The

basic nonattainment NSR requirements for the construction or

modification of major stationary sources in nonattainment areas and the

ozone transport region include the requirement that the lowest

achievable emission rate technology be installed, and that the

increased emissions of the nonattainment pollutant from the proposed

new major source or major modification be offset by actual emissions

decreases of the same pollutant from one or more existing sources. The

offsets may come from the same nonattainment area or another

nonattainment area of equal or higher classification as long as the

offsetting emissions contribute to the air quality problem in the area

where the decrease is being credited. As with PSD, the NSR requirements

for control technology application and offsets do not adequately

account for precursor activities or for the complexities associated

with atmospheric chemistry.

Any revised ozone and PM NAAQS may suggest that existing

implementing guidance, EPA's nonattainment NSR rules, and the States'

nonattainment NSR programs will need to be reviewed and revised in

various ways to address the integrated implementation approach being

contemplated.

The FACA Subcommittee and work groups will look into how the

current PSD/NSR programs for ozone and PM-10 attainment, unclassifiable

and nonattainment areas could be adapted

[[Page 65777]]

or modified. Some PSD/NSR questions that may consider include:

Question: What types of mitigation procedures should be required of

major new or modified sources that would contribute to violations of

the revised NAAQS for ozone or PM, or to visibility impairment in

Federal Class I areas?

Question: Should PSD/NSR requirements reflect the potential for

broad intra and interstate nonattainment areas, control areas, and

regional haze planning areas that could result when addressing

implementation under revised NAAQS for ozone and PM?

Question: What approach should be developed for the treatment of

ozone and fine particle precursors for PSD/NSR applicability purposes?

Question: Should the PSD/NSR programs allow for precursor

substitutions when environmentally beneficial to meet offset and

control technology requirements?

Question: How can availability, crediting, and location of

emissions offsets be restructured under a more regionalized

implementation strategy for PM?

6. Attainment Dates

Areas designated nonattainment with respect to a primary NAAQS are,

under the current statutory structure, required to achieve attainment

as expeditiously as practicable, but no later than 5 years from the

date the area was designated nonattainment. The EPA may extend this

date up to an additional 5 years. This extension may be a full 5 years

or any 1 year increment in between. Additionally, the Administrator may

grant two 1-year extensions.

With respect to a potential new secondary ozone NAAQS, areas

designated nonattainment are required, under the current statutory

structure, to achieve attainment of the secondary NAAQS as

``expeditiously as practicable'' following designation. Secondary

nonattainment areas are not bound to the same 10-year deadline as

primary areas.

Question: Given the preceding discussion, how should attainment

dates for primary and secondary NAAQS be established?

B. Phase II Issues

As discussed earlier in this notice, in Phase I, the FACA

Subcommittee and work groups will address air quality management

framework issues. The EPA plans to propose the resulting Phase I

strategy in mid-1997. Phase II of the integrated implementation

strategy will focus on more detailed control strategy development. The

EPA plans to propose the Phase II strategy in mid-1998. The Phase II

implementation issues include:

--Classifications of nonattainment areas;

--Control requirements (e.g., reasonably available control measures

including reasonably available control technology);

--Economic incentive programs;

--State implementation plan requirements;

--Overall control program integration;

--Measures of progress; and,

--Institutional processes.

All of these issues will be discussed in greater detail at a later

date. Interested readers are directed to EPA's TTN and WWW site for an

up-to-date status of the work groups and Subcommittee deliberations on

these issues.

V. Administrative Requirements

A. Executive Order 12866

Under Executive Order 12866, 58 FR 51735 (October 4, 1993), the

Administrator must determine whether the regulatory action is

significant and therefore subject to the Office of Management and

Budget (OMB) review and the requirements of the Executive Order. The

Order defines significant regulatory action as one that is likely to

result in a rule that may:

(1) Have an annual effect on the economy of $100 million or more or

adversely affect in a material way the economy, productivity,

competition, jobs, the environment, public health or safety or State,

local, or tribal governments or communities;

(2) create a serious inconsistency or otherwise interfere with an

action taken or planned by another Agency;

(3) materially alter the budgetary impact of entitlements, grants,

user fees, or loan programs or the rights and obligations of recipients

thereof; or

(4) raise novel legal or policy issues arising out of legal

mandates, the President's priorities, or the principles set forth in

the Executive Order.

Pursuant to the terms of Executive Order 12866, it has been

determined that this ANPR announces a significant regulatory action,

and as such, will be submitted to OMB for review. Any written comments

from OMB to EPA, any written EPA responses to those comments, and any

changes made in response to OMB suggestions or recommendations will be

included in the docket. The docket is available for public inspection

at the EPA's Air and Radiation Docket and Information Center, which is

listed in the ADDRESSES section of this notice.

B. Miscellaneous

Requirements under the Unfunded Mandates Act of 1995, the Paperwork

Reduction Act, and the Regulatory Flexibility Act will be addressed if

and when the Agency issues a proposed rule based on the comments

received on this ANPR.

List of Subjects in 40 CFR Part 51

Environmental protection, Administrative practice and procedure,

Air pollution control, Carbon monoxide, Nitrogen dioxide, Ozone,

Particulate matter, Sulfur oxides, Volatile organic compounds.

Dated: December 4, 1996.

Carol M. Browner,

Administrator.

Appendix

Definitions

Annual sulfate conversion: Although significant gas phase

transformation of sulfur dioxide occurs, aqueous phase oxidation is

believed to be responsible for the majority of annual sulfate

conversion in the Eastern U.S.

``Best'' and ``worst'' days: Can be defined as the average of

the 20 percent best and worst days, respectively, as measured in

terms of total light extinction.

Chemical sinks: Termination compounds that essentially remove

other compounds (e.g., nitric acid, hydrogen and organic peroxides).

Some ``sinks'' can eventually break down and reform precursor

compounds (e.g., peroxy acetyl nitrate, PAN).

Deciview: Derived from the light extinction coefficient and

describes changes in uniform atmospheric extinction that can be

perceived by a human observer. It is designed to be linear with

respect to perceived visual changes over its entire range in a way

that is analogous to the decibel scale for sound. A 1-deciview

change is roughly equivalent to a 10 percent change in visibility.

Improve: A federally-administered visibility monitoring network

for Federal Class I areas in several States that failed to submit

SIP's containing monitoring strategies as required in the 1980

visibility regulations. Intermediates: Include the short-lived

radicals (hydroxyl, hydro-, and organic-peroxy) which perform many

of the important atmospheric oxidation reactions.

Mandatory Federal Class I Areas: Areas designated as mandatory

Federal Class I areas are those national parks exceeding 6000 acres,

wilderness areas and memorial parks exceeding 5000 areas, and all

international parks which were in existence on August 7, 1977.

Precursors: Compounds which contribute or lead to the formation

of a secondary pollutant. For example, NOx and VOC are ozone

precursors.

Reasonably attributable: Visibility impairment, as defined in 40

CFR 51.301, that is ``attributable by visual observation or any

other technique the State deems appropriate.'' It includes impacts

to mandatory Federal Class I areas caused by

[[Page 65778]]

smoke, plumes or layered hazes from a single source or group of

sources.

Visibility regulations: See 45 FR 80084 (December 2, 1980)

(codified at 40 CFR 51.300-307).

VOC species: Most low molecular weight VOC species (which are

most prevalent in ambient air) are not expected to contribute

significantly to secondary aerosol formation. Certain aromatics, and

higher molecular weight alkanes and alkenes (>6 carbons) are

believed to be the major contributors to secondary organic aerosol

formation.

References

1. Appleton, E.L., ``A Cross-Media Approach to Saving the

Chesapeake Bay,'' Environ. Sci. Technol., 1995, 29, 550A-555A.

2. Dennis, R.L., Personal Communication, 1996.

3. EPA, 1996, ``PM Criteria Document.''

4. GCVTC, ``Report of the Grand Canyon Visibility Transport

Commission'' to the U.S. EPA, June 1996.

5. NESCAUM, ``Preview of 1994 Ozone Precursor Concentrations in

the Northeastern U.S.,'' 1995 Northeast States for Coordinated Air

Use Management, Boston, MA.

6. NRC, ``Rethinking the Ozone Problem in Urban and Regional Air

Pollution,'' National Academy Press, 1991.

7. NRC, ``Protecting Visibility in National Parks and Wilderness

Areas,'' National Academy Press, 1993.

8. Rao, 1996, Personal Communication, 1996.

9. Rao et al., ``Dealing with the ozone nonattainment problem in

the Eastern United States'', 1996.

10. Rao, S.T.E. Zalewsky and I.G. Zurbenko, ``Determining

Temporal and Spatial Variations in Ozone Air Quality,'' J. Air &

Waste Management Association; 1995,45, 57-61.

11. Trijonis, J. et al., ``Report 24--Visibility: Existing and

Historical Conditions--Causes and Effects,'' from Acidic Deposition:

State of Science and Technology,'' Volume III, National Acid

Precipitation Assessment Program, 1990.

12. U.S. Senate, Committee on Environment and Public Works, ``A

Legislative History of the Clean Air Act Amendments of 1990,''

Volume IV, p. 6093.

[FR Doc. 96-31343 Filed 12-12-96; 8:45 am]

BILLING CODE 6560-50-P